In current radio communication systems, a radio terminal connects to a radio base station and accesses the Internet via a core network. The radio terminal performs packet communication through a communication path (i.e., a bearer) established between an apparatus (e.g., a gateway apparatus) provided in the core network and the radio base station.
The radio base station and the gateway apparatus build a tunnel by encapsulating packets in order to provide the bearer. In this event, QoS (Quality of Service) information is stored in the outer header of a packet, whereby each communication apparatus in the communication system can perform packet forward control (priority control or the like) based on the QoS information. Hereinafter, a specific description will be given by illustrating EPS (Evolved Packet System) using E-UTRAN (Evolved Universal Terrestrial Radio Access Network) as disclosed in NPL 1.
Referring to FIG. 1, a UE (User Equipment: radio terminal) can perform communication through a logical path or logical channel (higher-level logical path) referred to as EPS bearer, which is created between the UE and a PDN GW (Packet Data Network Gateway). This EPS bearer is configured in such a manner that logical paths or logical channels (lower-level logical paths) terminated between the UE and an eNodeB (radio base station), between the eNodeB and a Serving GW, and between the Serving GW and the PDN GW, respectively, are concatenated by mapping. Here, the lower-level logical path between the UE and the eNodeB is referred to as radio channel, and the lower-level logical paths between the eNodeB and the Serving GW and between the Serving GW and the PDN GW are referred to as GTP (GRPS Tunneling Protocol) tunnel, as shown in FIG. 1.
Moreover, QoS information is associated with the EPS bearer. When forwarding packets through a GTP tunnel, each of the eNodeB, Serving GW, and PDN GW embeds QoS information in the outer header of a packet for the GTP tunnel, based on the QoS information associated with the EPS bearer. The eNodeB, Serving GW, and PDN GW perform packet forward processing (such as priority control) based on the QoS information.